Precast roof slab



yAug. 27, 1929. Q LATHROP 1,726,031

PRECAST ROOF SLAB Filed Feb. 7, 1924 l'g, f.

Patented ug. 27, 1929.

JAY LATHROP, 0F CINCINNATI, OHIO.

4rREcAsir nooFspAB.

Application l'ed February 7, y1924; Y Serial` No. 691,092.

My invention relates to slabs which are cast of gypsum or cementcomposition 'for use in laying roofs, floors, partitions, side walls,sidewalks, driveways, and like structures, particularly roofs andlloors. S'uc'h pre-cast slabs are used in place of monolithicconstruction, formed on the job by erecting forms, and pouring theplaster cement, gypsum or the like.

The practice at the present time 1n precast blocks for roofs and floors,is to provide a metal reinforced plaster block with unprotected edges.This not only results 1n the block chipping while being transported, butalso falls short of providing ample strength, so that only comparativelysmall sizes are practical to the end that the structure on which theblocks are laid, will take the large loads, and so that the unitsthemselves will possess sufficient strength of themselves due to theshort distance. to points of support from any point of application ofload to the individual block.

It is my object to provide a block which can be used in anytransportable and manipulatable size, in which the edges are protectedand proper anchorage provided for reinforcing rods orV mesh.

This object and other advantages to be noted I accomplish by thatcertain construction and arrangement of parts to be hereinafter morespecifically pointed out and claimed.

In the drawings:

Figure l is a section taken along one of the I-beams, forming theframework'of a building structure.

Figure 2 is a perspective of one of the pre-cast slabs.

Figure 3 is a perspective View of the metallic parts of one form of thepre-cast slab.

In making up the slab, I first make a form, and place therein along thesides thereof, a pair 0f rails 1, or they may be I-beams, channels orother accepted forms of metallic building material. I prefer railsbecause of their rounded top surfaces, and the fact that their basesextend beyond the vertical planes of the outer edges 0f the tops,thereby permitting me to abut two blocks against each v other, withprovision for a form between the two blocks into which plaster may bepoured.

I also place reinforcing rods, or mesh into the form, and preferably tiethem or it, into the rails. Thus in the example shown, the

it come either flush or a desired amountv above the tops of the rails.

The block will then be ready for use when hard, and will have sidesformed by exposed sides of the beams or rails 1, and eX- tendingthroughoutl the reinforcing rods or mesh, which not only gives strengthto the plaster or cement material, but ties the rails together.

The blocks may be made of any convenient size, as the reinforcements andrails or beams may be regulated in strength to suit the given purposeand size.

In laying the blocks on a structure of beams 4L the rail portions areset onto the top of the beams, extending across the span between beams.The plaster edges of the blocks will then extend along the beams.

By butting the blocks against each other, a space is left in thepreferred form, this space defined by the abutting edges of the bases ofthe rails, and the webs, and tops of the rails, into which spacesplaster or cement is poured as at 5. This plaster will key the blockstogether against any tendency to tilt, as will be evident fromexamination of Figure l.

Any cracks left between the edges of the blocks where they lie along thebeams can be also lilled with plaster or cement, and any desired coatapplied to the whole floor, roof, or other structure that has been sobuilt.

In shipment the rails protect the blocks from chipping, and in use therails transmit the load to the supporting structure. A maximum economyin construction cost and service, together with protection duringshipping at crucial points, is provided by my invention.

I Wish it understood that I have illustrated but one acceptable form ofmy invention, and that I wish to state in the claims that follow thepoints therein which I consider to be invention.

Having thus described my invention, what I claim as new and desire tosecure by Letmeans securing the bars to the metallicv 10 ters Patent, ispieces, said retaining means adapted to be A pre-Cast oeinentitiousconstruction slab tightened after the cementitious material comprising abody of cementitious material, has set, and the outer sides of themetallic 5 at least one set o'l opposite edges of said maypieces ofirregular shape y:for firmly holding terial formed Of'metallic pieces,reinforcing Cementitious material disposed between simbars extendingthrough the ceinentitious malarly cast slabs.

terial7 and holes in the metallic pieces through which the bars extend,retaining JAY C. LATHROP.

